Previously known methods of boresight alignment of small caliber weapons that utilized night viewing equipment used a second light, or boresight light, in the gun barrel of the weapon along with the aiming light mounted on the weapon for boresight alignment of the weapon. Alignment by the use of both lights required that a target at some distance away be used to zero in both light beams, i.e. beams from the boresight light and the aiming light, at a spot on the target. The operator that is aligning the weapon uses a night viewing device for observing the relative positions of the boresight light beam and the IR aiming light beam while the IR aiming light beam is zeroed in azimuth and elevation.